The present invention relates to a construction hoist system, comprising at least one mast having two adjacent parallel corner rails, a trolley running on the corner rails, and a motor on the trolley for driving the trolley along the corner rails. The system further comprises a first pair of connection members on the trolley, a work platform having a substantially flat work floor, and a second pair of connection members on the work platform. The work platform is releasably connectable to the trolley through interconnection of the first and second pairs of connection members with the work platform in a horizontal position in which the work floor is situated at a first level relative the trolley.
Such a construction hoist system is disclosed in SE-B-462 336. At one end the work platform of this known system is hinged on the trolley through the first and second pairs of connection members, and at the opposite end the work platform is hinged to another trolley on another adjacent mast through further pairs of connection members similar to said first and second pairs of connection members. As a result the work platform is allowed to tilt somewhat as it is hoisted or lowered between the two adjacent masts. A levelling device controls the trolley motors on the respective masts in response to sensors sensing the deviation of the work platform from a desired normal horizontal position of the work platform, so that the work platform substantially maintains its horizontal position during hoisting and lowering. Thus, the known system is limited to a two-mast configuration.
The prime object of the present invention is to provide a new construction hoist system, which is more versatile than the above known system and which is not limited to a two-mast configuration but can include a single-mast configuration as well.
Another object of the invention is to provide a versatile construction hoist system comprising simple and easy-to-use components to facilitate tailor-made configurations of the system for any buildings.
These objects are obtained by the construction hoist system described initially, which is characterised by a transport platform having a substantially flat load carrier floor, and a third pair of connection members provided on the transport platform, the transport platform being releasably connectable to the trolley through interconnection of the first and third pairs of connection members with the transport platform in a horizontal position in which the load carrier floor is situated at a second level relative the trolley, said second level being below said first level.
As a result, the advantage is obtained that besides the option of connecting the work platform, typically of a conventional type with a raised work floor, to the trolley there is also the alternative option of connecting the transport platform, typically with a low load carrier floor, to the trolley. Said second level relative the trolley is suitably selected so that the load carrier floor of the transport platform is close to or rests on the ground when the trolley is in its lowermost position on the mast, in order to facilitate material handling, i.e. loading and unloading the transport platform.
The construction hoist system of the invention preferably comprises an adapter having said third pair of connection members and being releasably connected to the transport platform. The adapter enables use of conventional types of transport platforms, which is cost beneficial.
In accordance with a simple and inexpensive design of the adapter, the adapter comprises a lateral beam, and two spaced apart posts extending upwardly from the lateral beam, said third pair of connection members being formed on the posts at their upper free ends.
For a single mast configuration, when the transport platform is relatively short, typically extending not longer than about 1.5 meters from the trolley, the construction hoist system of the invention suitably comprises a horizontal support beam, which is releasably attachable to the lateral beam of the adaptor to form a rigid unit consisting of the support beam and the adaptor. The support beam is releasably attachable to the trolley in such a manner that the load carrier floor of the transport platform is fixed in a horizontal position when the transport platform is attached to the trolley through the support beam.
In the case when the transport platform is relatively long, typically from two to about six meters, the construction hoist system of the invention comprises an additonal mast with an additional trolley, and an additional adapter, which is releasably connected to the transport platform at an end therof which is opposite the end of the platform which is provided with said first-mentioned adapter.
Suitably, said third pair of connection members of the first-mentioned adapter are hingeable on said first pair of connection members of the trolley and the pair of connection members on the additional adapter are hingeable on an additional pair of connection members on the additional trolley, such that the transport platform is tiltable about a horizontal axis through said third and first pairs of connection members and about a horizontal axis through the pairs of connection members on the additional trolley and the additional adapter.